As shown in FIG. 18, a flow measurement apparatus of this type hitherto has been provided with gas flow measurement means 401 that measures a gas flow in a gas passageway; flow increase detection means 402 that detects a flow increase on the basis of a measurement result; flow increase/decrease detection means 403 that detects an instantaneous increase/decrease change in gas flow incidental to the flow increase; appliance determination means 404 that determines initiation of use of a new gas combustion appliance when the instantaneous increasing/decreasing change is detected; and flow registration means 405 that registers an increase in gas flow detected by the flow increase detection means as a gas flow increase incidental to initiation of use of the new gas combustion appliance (see; for instance, Patent Document 1).
An attention is paid to the fact that an instantaneous increasing or decreasing change arises in gas flow at the time of initiation of use of a new gas combustion appliance and is followed by a stable gas flow, and initiation of use of a new gas combustion appliance is determined by means of the foregoing configuration at the time of determination of an increasing/decreasing change. Thereby, initiation of use of a new gas combustion appliance is determined by a simple method, and a gas increase resultant from use of the new gas combustion appliance can be registered.
However, the related-art configuration encounters a problem of difficulty in determining whether a flow increase results from use of the same appliance or a new gas combustion appliance.
To solve the problem, a flow measurement apparatus shown in FIG. 19 has an ultrasonic flow meter 407 serving as a flow measurement unit for measuring a flow in a passageway 406; a measured flow storage unit 408 that stores a flow value of the ultrasonic flow meter 407 and time information; learning appliance registration means 421 that registers, as appliance flow information, information about a flow measured for a given period of time; an appliance flow information storage unit 422 that registers and stores the measured flow information; and appliance determination means 411 that compares the measured flow information in the measured flow storage unit 408 with appliance flow information in the appliance flow information storage unit 422, thereby determining an appliance. Reference numeral 412 designates number-of-appliances determination means; 413 to 415 designate gas appliances; 416 designates a gas meter serving as a flow measurement apparatus; 417 designates a passageway cutoff valve; 418 designates an operation unit; 419 designates a gas passageway; and 420 designates appliance-specific flow computation means (see Patent Document 2).
The flow measurement apparatus enables storage and registration of measured flow information and determination of usage conditions of a plurality of appliances. So long as the type of an appliance (a hot water supply, a gas cooker, and the like) is previously registered, the appliance being used can also be specified.
There has also been proposed a gas meter that extracts from a flow pattern table a gas flow pattern detected from a gas supply line and a matched part flow pattern and that extracts from an appliance table a gas appliance matching a combination of the extracted partial flow patterns, thereby determining a gas appliance being used (see Patent Document 3).    Patent Document 1: JP-A-2002-174542    Patent Document 2: JP-A-2007-024750    Patent Document 3: JP-A-2003-149075